Abstract：When 3D cloud is visualized based on the method of direct volume rendering of meteorological data,if the grid data with low accuracy and few levels is used,the simulation data will be relatively rare in the vertical direction,resulting in very rough cloud surface and lack of authenticity in rendering effect.In order to solve this problem,this paper proposes a method to introduce random jitter into the texture noise so as to make the cloud surface more detailed and realistic.Firstly,3D Perlin noise texture is generated and sampled,and then fused with the original texture of meteorological data in different proportions.This method can make the three-dimensional cloud as a whole have better stereoscopic sense and better visual perception.In addition,although the reflection and absorption of light have been simulated by using numerical simulation to draw clouds,the scattering effect of light has not been involved,so the sense of reality of clouds drawn by numerical simulation is still insufficient.In order to draw a more realistic 3D cloud,this paper combined Cook Torrance lighting model and bidirectional reflection distribution function(BRDF）to improve the traditional lighting model.This improved model takes the effect of material microplane on illumination into consideration,and when applied to the visualization of 3D cloud,the 3D cloud simulation effect with strong sense of reality can be obtained.
2021, Vol. 42 
